Rather than attempt a blurb-type description myself - never a good idea - I shall quote from Magnum Opus's own summary:
ABOUT THE DRAGON WARRIORS ROLE-PLAYING GAMEDW belongs to a very different tradition of fantasy from Mirabilis (as different, indeed, as Jack Vance and Lord Dunsany) but the connection is not as tenuous as it seems. Not only did Leo devise the Rathurbosk, which he did a great painting of, he also helped create the basic map of the whole world of Legend.
Dragon Warriors is a fantasy role-playing game of adventure, magic, folklore, superstition and horror. The players take on the roles of gallant heroes in a world of fantasy who undertake dangerous missions and adventures, pitting themselves, their wits, their weapons and their magical abilities against any number of foes and challenges. Some do it for money, some for honour, and some for darker, more personal reasons.
The game is set in a world known as Legend, loosely based on Europe at the time of the medieval crusades. Human civilisation has spread across the world, but its links are fragile and are often broken by conflict, invasion, or reasons natural or supernatural. Man has learned something of the art of magic, though spell-casters are widely feared by normal folk. Creatures from folklore and myth roam outside the human communities, or sometimes inside them, spreading fear and ruin. And there are ancient quests and long-dormant discoveries to be unearthed by the brave, and riches and status to be gained.
The world of Dragon Warriors feels familiar but at the same time it is a place filled with threats and the unknown. The further you stray from home, the stranger the places you will encounter. The desolate tundra and pine forests of Krarth - reached by crossing the Rathurbosk, a magical mile-long bridge-city built over a gouge between two continents. The ruins of the city of Spyte, destroyed by its mad rulers the Magi whose descendents still control Krarth today. The peril-filled tropical jungles of Mungoda that grow over the faded remains of dead civilisations - jungles now home to the Volucreth bird-men, who hunt humans like animals. The New Selentine Empire, desperate to recapture the glories and power it held in the previous millennium. The Nomad Khanates. The Ta'ashim lands, steeped in magical stories and now in uneasy truce with Principalities of the Crusades. The great city of Ferromaine where money is king and anything can be bought if the price is right. And much more.
I was living at that time in Abbeville Road in South London. Leo had come up to stay the weekend and, as often happened, we got to talking about our latest projects. I had to create a setting for Dragon Warriors, the way Lord of the Rings has Middle Earth, but the only part Oliver and I had worked out in detail up till then was Ellesland, the setting for the first five books. With book six looming we needed to give players a full worldbook with details of all the other countries we had so far only mentioned in passing. As Oliver was wrapping up book five, it was high time I made a start on Legend but so far hadn't got much further than sketching a few ideas on the back of that familiar envelope...
At which point Leo grabbed a big sheet of tracing paper from his bag and drew the outline map of the DW world. Just like that. And then we starting riffing on what each bit of the world might contain, and that's when the Rathurbosk got added to the world - and the gothic idea of the degenerate descendants of the original Magi, many of whose armorial emblems Leo drew on the spot. The map above is by Russ Nicholson, and marvellous it is indeed, but I also treasure that original scrappy blueprint map that Leo drew.